A mobile power supply, also known as a power bank, is a portable charger that integrates power supply and charging functions. It can supply power or stand-by charging to a variety of digital products such as mobile phones, tablet computers, notebook computers, digital cameras, handheld game consoles, and portable sound boxes anytime and anywhere. The mobile power supply generally uses lithium batteries as a storage medium. Due to the advantages of small size, large capacity, and moderate price, lithium batteries have been widely used. The housing of the mobile power supply usually includes a charging interface and a discharging interface. The most common type of interface is Universal Serial Bus (USB), which is an external bus standard originally used to regulate the connection and communication between computers and external devices, and has been widely used in various mobile portable devices ever since.
With the increase of the battery capacity of mobile devices, the battery life has been greatly improved, but the increase of the battery capacity also means that it takes longer to charge. Charging with a maximum power of 5 V and 500 mA using a standard USB 2.0 interface takes several hours for a 3000 mA battery to fill up, which give the users a really bad experience. Therefore, various USB interface-based fast charging technologies have emerged. These fast charging protocols mainly include USB Battery Charging protocol, Qualcomm Quick Charging Protocol, Huawei Fast Charger Protocol, Samsung Adaptive Fast Charging Protocol, Mediatek Pump Express Charging Protocol and Apple Fast Charging Protocol. These fast charging standards use high-current or high-voltage charging methods which can charge the battery of the mobile phone in a short period of time, or allow the mobile phone to run for several hours by charging for five minutes in case of emergency, thus getting rid of the extra-long waiting time for charging.
In the prior art, the function of the mobile power supply is single and is usually limited to supplying power to the mobile devices, while common mobile devices (such as mobile phones and tablet computers) often need to expand external storage. If the storage medium can be integrated in the mobile power supply, and the USB interface can be used for charging and data communication simultaneously, that is, when charging a mobile device, the storage medium in the mobile power supply can be accessed through the mobile device (such as an APP installed thereon), the function of the mobile power supply can be expanded and the user experience can be enhanced.
Furthermore, both the discharging interface of common mobile power supplies and the charging interface of mobile devices represented by the Android mobile phone are USB interfaces. When charging an Android mobile device from the mobile power supply using a USB charging line, the Android mobile device first detects the maximum discharging power of the mobile power supply according to the fast charging protocol, and then selects the maximum charging power to charge itself according to its own power receiving capacity. The fast charging protocol generally stipulates that fast charging can only be performed when the discharging interface of the mobile power supply is in a single charging mode. When the discharging interface of the mobile power supply is in a charging and communication mode, that is, when USB data communication is allowed while charging, charging can only be performed in a mode of 5 V and 500 mA at maximum. That is, when USB data communication is allowed, the mobile device can only be charged with a maximum power of 2.5 W. The above-mentioned fast charging refers to charging the mobile device with a power exceeding 2.5 W.
If the mobile device can switch between the single charging mode and the charging and communication mode to ensure that the mobile device can perform data communication with the mobile power supply and can also rapidly charge the mobile device when there is no data communication, the function of the mobile power supply can be expanded while enhancing the user experience.